Question

Resolva a equação matricial:

Answer 1

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$\begin{pmatrix}\sf2&\sf1\\\sf1&\sf-3\end{pmatrix}\begin{pmatrix}\sf x\\\sf y\end{pmatrix}=\begin{pmatrix}\sf 7\\\sf7\end{pmatrix}\\\begin{pmatrix}\sf2\cdot x+1\cdot y\\\sf1\cdot x-3\cdot y\end{pmatrix}=\begin{pmatrix}\sf7\\\sf7\end{pmatrix}\\\begin{cases}\sf 2x+y=7\\\sf x-3y=7\end{cases}\\\underline{\rm multiplicando~a~1^{\underline a}~ equac_{\!\!,}\tilde ao~por~3:}\\+\underline{\begin{cases}\sf6x+\diagdown\!\!\!\!\!3y=21\\\sf x-\diagdown\!\!\!\!\!\!3y=7\end{cases}}\\\sf 7x=28\\\sf x=\dfrac{28}{7}$

$\sf x=4\\\sf 2x+y=7\\\sf 2\cdot4+y=7\\\sf 8+y=7\\\sf y=7-8\\\sf y=-1\\\huge\boxed{\boxed{\boxed{\boxed{\sf S=\{4,-1\}}}}}\blue{\checkmark}$